Method of producing metal working tools



sept 8, 1981. w C PRUL mmm.

IN VEN TOR. W. C. SPROU Patented sept. 8, 1931 .UNITED STATES PATENTOFFICE WILLIAM c. srRoUL, or nooxr'onn, ILLINors, ssIGNoR To THEInc-ERsoLL MILLING MACHINE COMPANY, or nocKroRD, rLLINors, AconPoi-:Aa'ron or rLLINoIs METI-IOD OE :PROD'UCING IVIETAL WOR'KINGTOOLS Applicatiqn filed May a,

The present invention relates in general to metal Working tools and hasparticular reference to that type of tool in which one or more insertedcutter teeth are rig'idly and detachably secured in a rotary head, baror the like mounting.

The application of the invention in the present instance is showninconnection With a milling cutter of the face mill type. Frequently thesecutters are referred to in trade as cone head cutters due to the frustumshape of the head.

One diificulty in seeking a practical solution of the problems involvedin the production of these types of cuttersis concerned primarily inholding the teeth rigidly in an open-ended slot and at the same timeallowing for adj ustment of the teeth in a direction parallel with theaxis of the head. Many solutions have been suggested such asinterlocking the teeth in the head slots by the use of serrations,sometimes formed in the Walls of the head slots and in the teeththemselves. In other instances, the use of shoes, keys and the likeaccessories have been employed. The

` use of such accessories is not to be tolerated if it is at allpossible to get alongwithout them because they add to the cost ofproduction and are theoretically wrong. One of the important objects ofthe present invention is to provide means such as serratons or the likefor interlocking the teeth in the slots of the head and to place theseserrations in the base of the slot Where they are most needed,

keys or the like.

Briefiy, the salient feature of the invention resides in providingserrations vin the base of a tooth slot in a milling cutter or the likehead With the serrations extending cross- Wise to the axis of rotationof the head' and to equip the cutter tooth With 'serrations on itsunderside to interlock with the serrations thus provided for in the baseof the slot.

It is not uncommon to cut serrations in the base of a slot in a millingcutter head When the serrations extend longitudinally or parallel Withthe axis of the head but to produce these serrations crosswise in theslot is entirely a difiierent matter. It is only after ex- Without theaid of such accessories as shoes,

1930. Serial NO. 419,4-25.

ercising considerable inventive ingenuity that it has been possible todevise a method of producing the serrations in the base of the slotcrosswise to the axis of the head. The method of rednci'ng the inventionto practice is also a salient feature of the invention and one of itsimportant objects.

W nile the foregoing statement is indicative in a general Way of thenature of the invention other objects and 'advantages will be apparentupon a full understanding of the construction and co-operativerelationship of the several parts of the tool.

One method of producingl the serrations in the base of the teeth slotsis explained herein but it will be understood that the in- Vention issusceptible to variations without departing" from the spirit of theinvention as defined in the subjoined claims.

In the accompanying drawings:

Fg. 1 is a View in perspective of a portion of a milling cutter, showingone application of the present invention; o

Fig. 2 is a top plan view of a portion of a milling cutter, showing theapplication of the invention;

Fig. 3 is a View in cross section, taken on the line 3-8, Fig. 2;

Fig. 4 is a detailed View in side elevation of a portion of a millingcutter head, illustrating `the method of reducing the present inventionto practise;

Fig. 5 is a detailedpperspectiveview of cutter tooth made in accordanceWith the invention; and

Fig. 6 is a detail perspective view of the invention as used inconnection With a Wedge type of holding means.

Since the invention isV especially adapted for use in connection Withinserted tooth milling cutters this particular use has been selected inthe accompanying drawings and in which part 5 represents a portion of amilling` cutter head the Vsame having' a plurality of circumf'erentiallyspaced slots for the re- 3 ception of the inserted crutter teeth 6.These ,teeth are rigidly and detachably fastened in the slots byclamping heads7 which are made to straddle each of pair of teeth. Eachof the clampingheads 7 is made With a tapped hole into which is threadedthe end 8 of a bolt 9. The bolt is inserted through a hole which isdrilled through the head 5 from the outer to the inner circumference.The hole is also countersunk to aecommodat-e the head 10 of the boltwhich in turn is made with a key socket 11 so that the bol-t may beturned to release or tighten the clamping heads 7.

In addition to the clamping device for rigidly and detachably holdingthe teeth in the slots additional means is employed to co-operatetherewith. In this connection attention is now invited to the serrationson the bottom of the teeth and in the base of the head slots. Theseserrations according to the present invention are preferably made on theorder of threads. The reason foi` which will be hereinafter explained.

It has not been uncommon to cut serrations in the base of the head slotsand match them with serrations on the underside of the cutter teeth butthese serrations have always extended longitudinally of the slots 01' inother words in a direetion parallel or substantially parallel with theaXis of the head. In cases where the serrations were provided crosswisesubstantially crosswisc to the axis of the head it has been necessary touse shoes, keys or the like. The present invention teaches a methodwhereby these serrations may be produced in the base of the head slotand extended crosswise orsubstantially crosswise to the aXis of thehead. In reducing the invention to practice a series of holes 12 aredrilled through the thickness of the head 5 at spaeed intervals aroundthe same. The holes being then tapped as shown in dotted lines in Fig. 4then the metal between the dotted lines ll is cut away to leave theslots, the result being a slot with half-threads or thread likeserrations in the base thereof. The cutter teeth 6 are serrated acrossthe bottom to leave half-threads corresponding to the thread likeserrations in the base of the slots. The thread like serrations on thebottom of the teeth merge into the sides of the teeth and correspond tothe thread like serrations in the bottom of the slots and in thisconnection it should be pointed out that the width of the slots shouldbe less than the diameter of the root of the threads tapped as at 13 toproperly accommodate the teeth without lost motion.

A eutter assembly construeted in accordance with the present inventionprovides an unusually convenient means of adjusting the teeth parallelor substa-ntially parallel with the axis of the head and also avoids anypossibility of the teeth moving in the slots in a. direction parallel orsubstantially parallel with the axis of the head.

In Fig. 6 the serrations are shown in connection with a. wedge type ofholding means.

Having thus described and shown an embodiment of this invention, what Iclaim and desire to secure by Letters Patent of the United States is:

1. In the production of inserted tooth metal working tools wherein aplurality of cutter teeth are interlocked in slots made to receive themin a head member, the method which consists in boring a series of spacedholes in the side of the head member, threading said holes, Cutting awaythe metal of the head member between its periphery and the holes toleave slots of a width substantially that of the diameter of the crestsof the threads and Cutting thread like serrations on the bottom of thecutter teeth to interlock with the thread like serrations thus producedin the head slots when the teeth are inserted in said slots.

2. In the production of inserted tooth metal working tools wherein oneor more cutter teeth are interlocked in a head member, the method ofproducing a slot in the head member for the reception of the tooth andprcvidng thread like serrations in the base of the slot to interlockwith mating serrations on the botton; of the tooth, which consists intapping a hole through the thickness of the head member slott-ing thehead member from the tapped hole to the periphery of the member withthev width of the slot substantially equal to the diameter of the crestof the threads.

8. In the production of inserted tooth metal working tools wherein oneor more eutter teeth are interlocked in a head member, the method whichconsists in tapping a hole in the head member, cutting away the metal ofthe head member between its periphery and the tapped hole to leave aslot and cutting thread like serrations on the bottom of the euttertooth to interlock with the threads in the head slot when the tooth isinserted in the slot.

Signed at Roekford, in the county of Tinnebago, and State of Illinois,this 29 day of April, 1930.

TILLIAM C. SPROL.

